The present invention relates to a sound producing device and an electronic instrument provided with the sound producing device.
An electronic instrument such as a portable telephone is provided with a sound producing device having a sound producer for producing telephone ring. The sound producing device is mounted in a case of the electronic instrument.
The sound emitted from the sound producing device is reflected from walls in the case. Consequently, reflected sound waves interfere with each other or are attenuated, which renders the sound to be indistinct. The attenuation of the sound waves causes the sound pressure to reduce. If the sound pressure reduces in the portable telephone, the telephone ring can not be confirmed.
In order to resolve the above described problems, it is necessary to emit the sound without leaking the sound in the case.
FIG. 5 shows a conventional sound producing device having a device for preventing the leakage of the sound. A sound producing device 1 is securely mounted on a substrate 2 secured to a case 3 of a portable telephone as an electronic instrument. The sound producing device 1 has a buzzer (not shown) as an electroacoustic transducer.
The sound producing device 1 has a sound discharge hole 1a, and the case 3 has a sound discharge hole 3a opposite the sound discharge hole 1a. A sound guide pipe 5 is provided between walls surrounding the sound discharge holes 1a and 3a so as to discharge the emitted sound without leaking in the case 3.
However, the sound guide pipe 5 causes the number of parts of the sound producing device 1 and the number of steps for manufacturing the device to increase. Further, it is difficult to accurately coincide the sound guide pipe with both the holes 1a and 3a. 